Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 344)

Product Overview
Appendix A
A –12
Port Isolation
Port Isolation Isolation voltage
PRT1 backplane to port 500V dc
PRT2 backplane to port 500V dc
PRT1 and PRT2 PRT1 to PRT2 500V dc
Important: Port DH485 is not isolated.
Clock/Calendar Accuracy
Specification Range
u
±
1 minute/month @ 25
°
C
accuracy
+ 0, – 6 minute/month @ 60
°
C
Math
Precision Range
8 significant digits  1E –127 to  .99999999E +127
Maximum Communication Distances
Communication Maximum distance allowed meters (feet)
rate (bit/s) RS-232 RS-423 RS-422 RS-485
300 15 (50) 15 (50) 1230 (4000) 1230 (4000)
600 15 (50) 15 (50) 1230 (4000) 1230 (4000)
1200 15 (50) 15 (50) 1230 (4000) 1230 (4000)
4800 15 (50) 15 (50) 1230 (4000) 1230 (4000)
9600 15 (50) 15 (50) 1230 (4000) 1230 (4000)
19200 15 (50) 15 (50) 1230 (4000) 1230 (4000)
Important: Use the RS-232 jumper settings for JW8 or JW9 when
communicating in RS-423 mode (page 1 -9). RS-423 devices should be
unterminated and cable length should be a maximum 50 ft.